1. Graphics Lab @ Korea University Computer Animation Computer Graphics

2. Graphics Lab @ Korea University Computer Animation What is Animation? Make objects change over time according to scripted actions What is Simulation? Predict how objects change over time according to physical laws 2

3. Graphics Lab @ Korea University Historically there are 3 major types of animation: 1.Hand Drawn Animation 2.Stop Motion Animation 3.Computer Animation 3 Types of Animation

4. Graphics Lab @ Korea University Done by an artist who draws each character and movement individually Very time consuming to have to draw, then colour, then photograph each picture Draw pictures first, then colour them on celluloid, then they take pictures and animate them Very expensive due to hours of labour involved Examples: Older Disney Movies i.e. Bambi, Fox and Hound, Cinderella etc. Hand Drawn Animation

5. Graphics Lab @ Korea University Hand Drawn Animation

6. Graphics Lab @ Korea University Can be done by virtually anyone, with no extensive training Does not take that much time relative to the other 2 methods Uses jointed figures or clay figures that can be moved to make motions Take still pictures of the individual movements, then use relatively inexpensive computer software to animate Stop Motion Animation

7. Graphics Lab @ Korea University Stop or Model Animation

8. Graphics Lab @ Korea University Animated Movies: Million dollar industry; 1- 20 millions spent on each movie Animation & Computer Graphics Effects are used in movies frequently Animation uses

9. Graphics Lab @ Korea University Outline Principles of Animation Keyframe Animation Articulated Figures 9

10. Graphics Lab @ Korea University Principle of Traditional Animation – Disney – Squash and Stretch Slow In and Out Anticipation Exaggeration Follow Through and Overlapping Action Timing Staging Straight Ahead Action and Pose-to-Pose Action Arcs Secondary Action Appeal 10

11. Graphics Lab @ Korea University Squash and Stretch 11 Squash Stretch

12. Graphics Lab @ Korea University Squash and Stretch The most important principle is "squash and stretch", the purpose of which is to give a sense of weight and flexibility to drawn objects. It can be applied to simple objects, like a bouncing ball, or more complex constructions, like the muscles of a human face. A figure stretched or squashed to an exaggerated degree can have a comical effect. 12

13. Graphics Lab @ Korea University Squash and Stretch In realistic animation, however, the most important aspect of this principle is the fact that an object's volume does not change when squashed or stretched. If the length of a ball is stretched vertically, its width (in three dimensions, also its depth) needs to contract correspondingly horizontally. 13

14. Graphics Lab @ Korea University Slow In and Out 14

15. Graphics Lab @ Korea University Slow in and Slow out The movement of the human body, and most other objects, needs time to accelerate and slow down. For this reason, animation looks more realistic if it has more drawings near the beginning and end of an action, emphasizing the extreme poses, and fewer in the middle. 15

16. Graphics Lab @ Korea University Slow in and slow out 16

17. Graphics Lab @ Korea University Anticipation 17

18. Graphics Lab @ Korea University Anticipation Anticipation is used to prepare the audience for an action, and to make the action appear more realistic. A dancer jumping off the floor has to bend his knees first; a golfer making a swing has to swing the club back first. 18

19. Graphics Lab @ Korea University Exaggeration Exaggeration is an effect especially useful for animation, as perfect imitation of reality can look static and dull in cartoons. The classical definition of exaggeration, employed by Disney, was to remain true to reality, just presenting it in a wilder, more extreme form. Other forms of exaggeration can involve the supernatural, alterations in the physical features of a character, or elements in the storyline itself. 19

20. Graphics Lab @ Korea University Exaggeration cgvr.korea.ac.kr 20

21. Graphics Lab @ Korea University Follow through and overlapping actions. "Follow through" means that loosely tied parts of a body should continue moving after the character has stopped and the parts should keep moving beyond the point where the character stopped to be "pulled back" only subsequently towards the center of mass. 21

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24. Graphics Lab @ Korea University Timing and Motion Gives meaning to movement. Proper timing is critical to making ideas readable. Examples: 1. Timing: tiny characters move quicker than larger ones. 2. Motion: can define weights of objects.

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26. Graphics Lab @ Korea University 4. Staging A clear presentation of an idea. Some Techniques: 1.Use motion in a still scene or use of static movement in a busy scene. 2.Use of silhouettes (to the side)

27. Graphics Lab @ Korea University Straight Ahead Action and Pose-to-Pose Action 1. Straight Ahead Animator start from first drawing in the scene and draw all subsequent frames until the end of scene. 2. Pose-to-Pose Animator plans actions, draws a sequence of poses, in between frames etc.

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29. Graphics Lab @ Korea University Arcs Visual path of action for natural movement. Makes animation much smoother and less stiff than a straight line.

30. Graphics Lab @ Korea University

31. Secondary Action Action that results directly from another action. Used to increase the complexity and interest of a scene. Example: Body movement is the primary action, facial expression is the secondary action

32. Graphics Lab @ Korea University Appeal Refers to what an audience would like to see. Character cannot be too simple (boring) or too complex. Examples: Avoid mirror symmetry, assymmetry is interesting.

33. Graphics Lab @ Korea University Role of Personality Animator’s first goal is to entertain. Success of animation lies in the personality of the characters. Conclusion Hardware/Software are simply not enough, these principles are just as important tools too.

34. Graphics Lab @ Korea University That’s All Folks!

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36. Graphics Lab @ Korea University Outline Principles of Animation Keyframe Animation Articulated Figures 36

37. Graphics Lab @ Korea University Keyframe Animation Define Character Poses at Specific Time Steps Called “Keyframes” 37

38. Graphics Lab @ Korea University Keyframe Animation Interpolate Variables Describing Keyframes to Determine Poses for Character in between 38

39. Graphics Lab @ Korea University Inbetweening Linear Interpolation Usually not enough continuity 39

40. Graphics Lab @ Korea University Inbetweening Spline Interpolation Maybe good enough May not follow physical laws 40

41. Graphics Lab @ Korea University Outline Principles of Animation Keyframe Animation Articulated Figures 41

42. Graphics Lab @ Korea University Articulated Figures Character Poses Described by Set of Rigid Bodies Connected by “Joints” 42 Base Arm Hand Scene Graph

43. Graphics Lab @ Korea University Articulated Figures Well-Suited for Humanoid Characters 43 R R R R

44. Graphics Lab @ Korea University Articulated Figures Joints Provide Handles for Moving Articulated Figure 44

45. Graphics Lab @ Korea University Example: Walk Cycle Articulated Figure: 45 Hip Knee Foot Upper Leg Ankle Lower Leg

46. Graphics Lab @ Korea University Example: Walk Cycle Hip Joint Orientation: 46

47. Graphics Lab @ Korea University Summary Animation Requires... Modeling Scripting Inbetweening Lighting, shading Rendering Image processing 47